August in Oklahoma is a transitional bridge between intense summer heat and the productive cool-season growing period. While temperatures remain high, this month marks the start of the second growing season, offering the opportunity for a bountiful autumn harvest. Planning and planting now takes advantage of the warm soil and eventual cooler nights that make fall gardening rewarding. Success requires shifting focus from summer maintenance to establishing new crops and preparing for the next year.
Edibles for the Autumn Harvest
August is the window for planting edibles that will mature during the favorable weather of autumn. Root vegetables like carrots, radishes, and beets should be sown now. They benefit from warm soil for germination, while cooling temperatures later enhance their sweetness and texture. Leafy greens such as collard greens and leaf lettuce can also be direct-sown in mid-August for a continuous fall supply.
For a quick harvest, bush beans and summer squash can be replanted in the first few weeks of August, taking advantage of their short maturity time before the first frost. However, long-season crops require a head start to ensure a harvest before winter arrives. Broccoli, cabbage, and cauliflower should be planted as four- to five-week-old transplants by mid-August. These brassicas often perform better in the fall than the spring, producing higher quality heads due to the shift from warm days to cool nights.
Ornamentals and Spring Preparation
August is a strategic month for setting the stage for fall aesthetic display and future spring blooms. To enjoy color as the summer garden fades, cool-weather annuals can be planted toward the end of the month. Pansies and ornamental cabbage or kale are excellent choices that will provide vibrant color through the fall and often into the winter. These plants are tolerant of cooler temperatures and will thrive as the intense heat breaks.
August is the perfect time to purchase and plan for the next year’s ornamental garden, specifically for spring-blooming bulbs. While bulbs like tulips, daffodils, and crocuses are planted later in the fall, buying them now ensures the best selection and quality. Securing them in August allows for proper planning of location and grouping for visual impact, as these bulbs require chilling in the soil to initiate blooming.
Managing the Oklahoma August Environment
Planting new crops in August requires specific environmental management to overcome the intense summer heat. Surface soil temperatures can reach up to 140 degrees Fahrenheit, which is detrimental to seed germination and delicate seedlings. Providing afternoon shade for newly planted rows, perhaps with a shade cloth, can lower the soil temperature and reduce water evaporation. Deep and consistent watering is necessary to keep the seedbed moist, as seeds will not germinate if the soil at their planting depth dries out.
The high temperatures demand a focus on soil health, which may have been depleted by the summer growing season. Amending the soil with organic material like compost is beneficial. It improves aeration in clay soils and increases the water-holding capacity in sandy soils, providing necessary nutrients for the second season of growth.
Calculating the planting window is determined by the average first frost date. This date varies significantly across Oklahoma, ranging from mid-October in the Panhandle to early November in the southern regions. Gardeners must count backward from their local anticipated first frost date using the crop’s “Days to Maturity” to ensure the plant has enough time to produce a harvestable yield.
After harvesting the last of the summer crops, August offers the chance to sow cover crops in vacant beds. Options include oats or winter rye, which will protect the soil from erosion and improve its structure over the winter months.